1. Technical Field
The present invention relates to a development unit, a process cartridge and an image forming apparatus.
2. Related Art
In an image forming apparatus adopting an electrophotographic system, such as a copying machine or a printer, a toner image is formed on a charged body (for example, a photoreceptor), its toner image is transferred to a transferred body (for example, paper), and the toner image carried on the transferred body is fixed by a fixing unit. Herein, in order to form a toner image on the charged body, a development unit accommodating developer therein is arranged correspondingly to a development area of the charged body, and toner is made to fly from the development unit or the developer is rubbed, thereby to attach toner onto an electrostatic latent image formed on the charged body. On the other hand, as the developer, there are a single component developer composed of only magnetic toner or non-magnetic toner, and a two-component developer composed of toner and carrier.
In a development unit using the two-component developer, a developer stirring-transporting member is provided in a housing of the development unit. The developer stirring-transporting member of this stirring unit mixes the two-component developer in the housing and the new-supplied toner together, and makes the carrier and the toner of the two-component developer charged.
On the other hand, in the housing of the development unit, a magnetic member is disposed around a bearing portion, and the carrier in the developer is attracted to the magnetic member, thereby to form a so-called magnetic seal.